<p style='text-indent:20px;'>We are interested in the numerical approximation of solutions of nonlinear stochastic differential equations, that appear in financial mathematics. Here, we study the Aït-Sahalia model. We propose an explicit numerical scheme where we actually approximate the Lamperti transformation of the original stochastic differential equation and then transform back. The proposed method is domain preserving and is proven to converge strongly to the solution process with order at least <inline-formula><tex-math id="M1">\begin{document}$ 1 $\end{document}</tex-math></inline-formula> with no extra restrictions on the step-size <inline-formula><tex-math id="M2">\begin{document}$ \Delta $\end{document}</tex-math></inline-formula>. Numerical experiments verify the theoretical results.</p>